FrSky R9 and R9M radio control system is the first FrSky long range system which works in the frequency of 900MHz. The R9M module offers 4 switchable RF power outputs so you can choose the appropriate power for different flight situations. Compared to another FrSky 2.4GHz long range receiver like the L9R, the R9 receiver has a longer operating range up to 10KM and above. Moreover, the R9 is also a redundancy receiver which can connect to another receiver to ensure the security of your aircraft.